First-principles study of n- and p-type doping opportunities in LiGaO <sub>2</sub>
Klichchupong Dabsamut, Adisak Boonchun, Walter R. L. Lambrecht
Abstract
Abstract First-principles calculations are presented for Si, Ge, Sn doping of LiGaO 2 . Both Si <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="block" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mtext>Ga</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> and Ge <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="block" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mtext>Ga</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> are found to be shallow donors. Sn <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="block" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mtext>Ga</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> is found to be a somewhat deeper donor. The site preference is studied and all three group-IV dopants are found to favor the Ga over the Li site when the Fermi level is in the upper part of the gap, corresponding to n-type doping and for Li-rich growth conditions. The prospects for n-type doping are thus favorable. N <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="block" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mtext>O</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> is found to be amphoteric with both deep donor and acceptor type transition levels. Zn has a significant site competition between Zn <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="block" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mtext>Li</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> (donor) and Zn <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="block" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mtext>Ga</mml:mtext> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> (acceptor) levels, which would pin the Fermi level in the middle of the gap. Thus, p-type doping cannot be achieved with these dopants.